Thursday, March 10, 2016

Mysterious Circles Appearing in WesternU Buildings

Cue the X-Files theme.

As the new academic building for FIMS/Nursing starts to take shape and look more like the building depicted in the artist renderings, it always seems amazing that a 100,000 sq. ft. structure can go from lines on a blueprint to a functional, plumbed, hydroed, heated and cooled facilities that fits exactly where it was designed to go ... to the millimeter. So for someone who struggles to hang a series of pictures in a straight line, it boggles the mind the precision that it takes.

Construction is a bit of a mystery for those not in the industry. And there is something almost magical about seeing a building taking shape. It's almost like watching a movie based on a book as it jumps from the pages to be played out right in front of your eyes.

And once the building is complete, there are unique features that continue to be a mystery. For example, within the stairwells of many buildings there are several circular indents, seemingly cut into the concrete. They aren't randomly placed, they have a pattern to them - almost decorative. But are they?

Well, as it turns out, the answer is 'yes' and 'no'. According to FM Project Manager Glen Armstrong (PM on recent Ivey building and the new Engineering Building), this circular relief is the remanence of construction. Left both as a design feature, but also because of its functionality during a build.

When wet cement is poured for a wall it requires a form to hold it in place - like a jello mold. Usually the form material is wood. It's easy to work with, it's inexpensive and can be reused in some cases. To ensure the walls of the form don't fall to either side during pouring they are held together with a series of tie rods. The ties are then secured on either side of the form to keep the cement from collapsing inward (making a narrowing in the wall) or outward (making a bulge in the wall).

The image at right demonstrates the use of wood plyform sheathing (plywood, basically) and typical tie rods. When the reinforced concrete cures and the forms are removed, the spot where the circular cap once was is left as an indent, usually a few inches in diameter.

The tie is cut off snug to the concrete and remains buried in the wall with a small piece of the rod still sticking out in the middle the circular indent. And that's the functional part of the mystery.

That is particularly true when a stairwell is left unfinished (unpainted or unclad) and the concrete is left bare. It would appear incomplete if the holes were simply filled with mortar - similar to patched drywall that hasn't been repainted. There are three standard hole covering treatments. For unfinished walls, the typical filler is a flush or recessed plastic cover, like the ones found in the Health Sciences Building (pictured right). In some cases, the hole is patched with mortar to cover the exposed tie rod and can maintain a slight recess to break up the monotony of the flat concrete wall, similar to the Support Services Building. A third treatment is to epoxy the small piece of exposed tie rod. It is the most minimalist approach to covering the rod and an uncommon practice on campus.